Salamander Research Articles

Amphibian apocalypse: On the trail of the killer

A deadly disease is wiping out frogs and salamanders all over the world – but where did come it from?

Absence of infection with the amphibian chytrid fungus in the terrestrial Alpine salamander, Salamandra atra

1) Trier University, Biogeography Department, 54286 Trier, Germany 2) Department of Biology, Copenhagen University, Universitetsparken 15, 2100 Copenhagen, Denmark 3) Department of Evolutionary Biology, University of Vienna, Vienna, Austria 4) KARCH, Passage Maximilien-de-Meuron 6, 2000 Neuchâtel, Switzerland 5) Herpetology Department, Zoologisches Forschungsmuseum Alexander Koenig, Adenauerallee 160, 53113 Bonn, Germany 6) Department for Molecular Biodiversity, Zoologisches Forschungsmuseum Alexander Koenig, Adenauerallee 160, 53113 Bonn, Germany 7) Institut fur Evolutionsbiologie und Umweltwissenschaften, Universitat Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland

Thyroid Hormone Mediation in Skull Development of Siberian Newt, Salamandrella keyserlingi (Urodela: Hynobiidae), with Comparison to Other Species

Sequence and timing of cranial bones appearance and metamorphic transformation were compared in larvae of Siberian newt, Salamandrella keyserlingi (Urodela, Hynobiidae), reared under different levels of thyroid hormone (TH): i) normal, ii) high (in 1 and 10 ng/ml T 3 ), and iii) low (in 0.02% thiourea, TU, which inhibits thyroid gland activity resulting in TH deficiency). Cranial bones exhibit differential reaction to changes in TH level. Bones appearing in early larval ontogeny display no or only slight response to TH changes. At different TH regimes, they arise at the same stages and at the same age. Bones appearing later show reaction to TH changes: their appearance is accelerated and retarded in TH- and TU-treated larvae, correspondingly. The major response to TH alterations is displayed by ontogenetic events involved into metamorphic remodeling: they are greatly accelerated under TH-treatment and retarded in TH-deficiency. Most metamorphic events fail to occur under TH-deficiency. Comparison of TH-related changes in skull development of Ambystoma mexicanum ( Ambystoma tidae), Triturus vulgaris (Salamandridae), and S. keyserlingi showed that in these species the same bones differ in reaction to TH changes. A corollary of these differences is that in urodeles TH-dependence and TH-sensitivity of cranial bones change both in ontogeny and phylogeny.

On the diversity of the primary steps of embryonic development in the caudate amphibians

Literary data on the peculiarities of the egg cleavage process in various representatives of the order of caudate amphibians consisting of 10 families have been considered. It has been recognized that in considerable number of species of Plethodontidae, Cryptobranchidae, and some other families, the synchrony of divisions is lost already after the 8-celled stage of the cleavage in large, yolk-rich and unpigmented eggs. A"standard" cleavage of early embryos of caudate amphibians, which had been described in the text-books on developmental biology and consists approximately of 10 synchronous divisions of comparatively small eggs, is characteristic only of the families Ambystomatidae and Salamandridae including 19.3% of species within the order Caudata. However, within each of these families there seems to be a number of species with a "nonstandard" type of early cleavage. The evolutionary relationships between two main types of early embryogenesis within the order Caudata are discussed.

Effects of muscle dynamics and proprioceptive feedback on the kinematics and CPG activity of salamander stepping

Reference EPFL-CONF-168634doi:10.1186/1471-2202-12-S1-P158 URL: http://www.springerlink.com/content/240k7172657m180g/ Record created on 2011-09-05, modified on 2017-12-10

Development of the bony skeleton in two salamander species (Mertensiella caucasica and Chioglossa lusitanica: Salamandridae) with partial embryonization

168 The Caucasian salamander (Mertensiella cauca sica) and golden striped salamander (Chioglossa lusi tanica) are the most closely related taxa in the group of true salamanders belonging to the family Salaman dridae [1, 2]. In addition, they stand out among the other salamanders by a considerable similarity in their morphological constitution [3] and life style [3–5]. A study on the reproduction biology of these species has also demonstrated that they are very similar in a num ber of reproductive parameters, namely, both species reproduce in brooks and lay large (5–7 mm in diame ter) eggs in small clutches (on average, 17–18 eggs) [4–6]. These traits distinguish M. caucasica and C. lusitanica from the majority of the other true sala manders, characteristic of which is ovoviviparity or viviparity, and the remaining members of the family Salamandridae, newts, which lay considerably smaller eggs. On the other hand, the large size of the eggs and hatching of larvae at advanced development stages (as was demonstrated for M. caucasica [7]) suggest a pro nounced embryonization of development, i.e., transi tion of the initial stages in larval development to the embryonic period. Among amphibians, this evolutionary process leads to establishment of a direct development (lacking the larval stage), which is present only in members of the family Plethodontidae within the order Urodela. The effect of the degree of embryonization on the specific morphoge netic traits and, in particular, craniogenesis, has been also demonstrated for these amphibians [8, 9]. As we see it, a study of the skeletal development in the amphibian spe cies with partial embryonization of development will help to shed light onto the initial stages in the evolution path way that had led to direct development. For this purpose, we have studied the skeletal development of M. caucasica and C. lusitanica in the ontogenesis. Clutches of both salamander species were incubated under laboratory conditions; the embryos at late developmental stages (staring from limb differen tiation), larvae, and metamorphosing animals were regularly fixed with 10% formaldehyde and stained with alizarin red and alcian blue to detect bones and cartilages, respectively. The developmental stages were determined according to the table of M. caucasica normal development [7], which, except for some col oration traits, equally well described the C. lusitanica developmental stages. GENERAL BIOLOGY

Exploring Patterns and Extent of Bias in Estimating Divergence Time from Mitochondrial DNA Sequence Data in a Particular Lineage: A Case Study of Salamanders (Order Caudata)

In the practice of molecular dating, substitution saturation will bias the results if not properly modeled. Date estimates based on commonly used mitochondrial DNA sequences likely suffer from this problem because of their high substitution rate. Nevertheless, the patterns and extent of such expected bias remain unknown for many major evolutionary lineages, which often differ in ages, available calibrations, and substitution rates of their mitochondrial genome. In this case study of salamanders, we used estimates based on multiple nuclear exons to assess the effects of saturation on dating divergences using mitochondrial genome sequences on a timescale of ~200-300 My. The results indicated that, due to saturation for older divergences and in the absence of younger effective calibration points, dates derived from the mitochondrial data were considerably overestimated and systematically biased toward the calibration point for the ingroup root. The overestimate might be as great as 3-10 times (about 20 My) older than actual divergence dates for recent splitting events and 40 My older for events that are more ancient. For deep divergences, dates estimated were strongly compressed together. Furthermore, excluding the third codon positions of protein-coding genes or only using the RNA genes or second codon positions did not considerably improve the performance. In the order Caudata, slowly evolving markers such as nuclear exons are preferred for dating a phylogeny covering a relatively wide time span. Dates estimated from these markers can be used as secondary calibrations for dating recent events based on rapidly evolving markers for which mitochondrial DNA sequences are attractive candidates due to their short coalescent time. In other groups, similar evaluation should be performed to facilitate the choice of markers for molecular dating and making inferences from the results.

Watersnake and Salamander

Watersnake and Salamander

Salamanders of the Southeast

Salamanders of the Southeast

Tail autotomy and escape performance in a stream side salamander

Tail autotomy and escape performance in a stream side salamander

The effects of artificial night lighting on the nocturnal activity of the terrestrial red-backed salamander, Plethodoncinereus

The effects of artificial night lighting on the nocturnal activity of the terrestrial red-backed salamander, Plethodoncinereus

First record of salamander predation by a Liophis (Wagler, 1830) snake in the Venezuelan Andes

Information available so far is exceedingly meagre about the diet of the snakes included in the genus Liophis, one of the most diverse groups that inhabit ter - restrial ecosystems of South America. For the first time is documented the predation of a salamander by Liophis from Venezuela, including a brief overview on the altera - tion of montane and submontane Andean ecosystem and their effect on the natural dynamic.

Risks to Colombian Amphibian Fauna from Cultivation of Coca (Erythroxylum coca): A Geographical Analysis

The Colombian amphibian fauna is among the richest known in the world, with about 20 species of salamanders (order Caudata), 35 of the limbless caecilians (order Gymnophiona), and more than 700 species of frogs and toads (order Anura) recorded from localities within the country. The potential effects of exposure to glyphosate on amphibians arising from production of illegal crops (coca) were examined. The analysis was based on (1) behavior and ecology of species and (2) proximities of actual museum records to localities in which illegal crops are being grown and the subset of those that have been sprayed with glyphosate. Based on data on the location of amphibians collected in Colombia, records were obtained for 193 species (28% of the national diversity) of frogs and toads found in localities within 10 km of areas where coca is grown. Further analyses with ARC MAP software allowed for measurement of the direct distance separating collection locations for frogs, known coca fields, and areas where aerial spraying was being conducted. Records in or near coca fields included data for 11 of 13 families of frogs and toads known to be present in Colombia. Only Ceratophryidae and Pipidae were not reported from these locations and appear not to be at risk. For eight species (Dendrobates truncatus, Craugastor raniformis, Pristimantis gaigeae, Smilisca phaeota, Elachistocleis ovale, Hypsiboas crepitans, Trachycephalus venulosus, and Pseudis paradoxa) selected to represent several habitat preferences and life-cycle strategies, large areas of their distributions lie outside coca production regions and their populations as a whole are at low risk. For a limited number of species that barely enter Colombian territory, the consequences of coca production may be more serious and may have placed several species of frogs at risk. These include Ameerega bilingua, Dendropsophus bifurcus, Pristimantis colomai, P. degener, P. diadematus, P. quaquaversus, P. variabilis, and Trachycephalus jordani. Other species may also be at risk but exact numbers are unknown since few investigations were undertaken in these areas during the past 30 yr. The main ranges for these species were assumed to be in Ecuador.

Ranavirus Outbreak in North American Bullfrogs (Rana catesbeiana), Japan, 2008

To the Editor: Ranaviruses (family Iridoviridae) are emerging pathogens of farmed and wild amphibians and cause high mortality rates in these animals (1). These viruses are associated with massive population decreases of some species (2,3); outbreaks have been reported in the United States, Asia, Micronesia, and Europe. At the general meeting held by the International Epizootic Office in May 2008, iridoviruses of amphibians were added to the list of pathogens of wildlife that should be monitored (www.oie.int/aac/eng/Publicat/Cardsenglish/Ranavirus%20card_final.pdf, www.oie.int/eng/normes/fcode/en_chapitre_2.4.2.htm, and www.jcu.edu.au/school/phtm/PHTM/frogs/otherdiseases-viruses.htm). We report an outbreak of ranavirus disease in amphibians in Japan. A mass die-off of wild North American bullfrog (Rana catesbeiana) larvae was discovered in a 1,000-m2 pond in western Japan. The die-off lasted from September 10 through October 20, 2008, with an epidemic peak on September 20, during which several thousand carcasses were collected daily. No dead adults of R. catesbeiana or other amphibian species were found. Fish (families Cyprinidae and Gobiidae) in the pond were unaffected. Clinical signs in frogs were depression; lethargy; palpebral hyperemia; abdominal edema, petechiae, and erythema on the ventral surface; skin ulcers; limb and tail necrosis; and emaciation. Pathologic changes were similar in all larvae. At necropsy, subcutaneous edema, body cavity effusions, and swollen and friable livers were observed. Histologic examination showed extensive glomerular necrosis with renal tubular hyaline droplet degeneration (Appendix Figure) and various degrees of hepatic cell degeneration and necrosis. Myxosporidia were not observed within any renal tubules. Electron microscopy showed cytoplasmic ranavirus-like particles within glomerular endothelial cells. These particles were icosahedral with a diameter of ≈120 nm. Bacterial colonies were observed on the skin and within multiple organs in some larvae examined. These colonies were interpreted to be opportunistic organisms and microbial cultures were not performed. PCR with primers M153 and M154 (4) amplified a ranavirus-specific gene encoding major capsid protein (MCP) from 18 bullfrog specimens. DNA sequences (584 nt, which did not include primer-annealing regions) obtained from 5 PCR products randomly selected by direct-sequencing were identical. These sequences showed highest similarities with those of R. catesbeiana virus TW07–440 (GenBank accession no. {type:entrez-nucleotide,attrs:{text:FJ207464,term_id:459465026,term_text:FJ207464}}FJ207464); only 1 nt difference was observed and this difference resulted in an amino acid substitution. Amplifications with several sets of primers (M68/M69, M70/M71, M72/M73, M84/M85, and M151/M152) (4) and sequencing were conducted. We determined MCP DNA sequences of 1,472 nt that included the complete coding region (nt positions 17–1408, 1,392 nt) and proximal flanking regions. Sequences were deposited in the DNA Data Bank of Japan/GenBank/European Molecular Biology Laboratory DNA databases under the accession no. {type:entrez-nucleotide,attrs:{text:AB474588,term_id:242392411,term_text:AB474588}}AB474588. Phylogenetic analysis showed that virus detected in this study, designated RCV-JP, showed greater similarity to TW07–440 virus than to other ranaviruses, including tadpole edema virus (5), frog virus 3 (6), and R. catesbeiana virus Z (7). Liver tissues of fish (Gnathopogon spp.) that cohabitated the pond, but showed no external signs of disease, were positive for ranavirus by PCR using primers M153 and M154. Further sequence analyses are ongoing, and additional investigations of other amphibians and fishes are needed. Live freshwater fish from several countries have been imported into Japan. However, large amounts (<1,300 tons in 2007) of live aquaculture products, including eels and other fishes, have been imported from Taiwan into Japan (www.customs.go.jp/tariff/2007_4/data/03.htm). Given that viruses that originate in Japan and Taiwan are similar, the ranavirus we detected was likely imported into Japan in an infected aquatic organism. However, an epidemiologic survey will be necessary to determine the source of the ranavirus in the pond studied. Likewise, this virus may be endemic to Japan, and a survey of native and foreign free-ranging amphibians should be conducted. Molecular analysis of ranaviruses detected in these surveys will be necessary to differentiate endemic viruses from introduced viruses. Japan is located at middle latitudes and has a temperate climate. This country has long been geologically isolated from Asia. This isolation has resulted in the development of many diverse species of amphibians in Japan; 23 species of the order Caudata and 35 species of the order Anura. Of these species, 49 (84%) are native and 36 (62%) are listed by the Ministry of the Environment as threatened species (8). R. catesbeiana frogs were introduced into Japan in 1918 as a food animal, and raising them by aquaculture was widely attempted. Although they are no longer cultured, feral populations have become established throughout Japan (9). Ranavirus in R. catesbeiana frogs represents a serious threat to amphibians throughout Japan.

Decoding the mechanisms of gait transition in the salamander using robots and mathematical models

Reference EPFL-CONF-159633doi:10.1016/j.cbpa.2009.04.247View record in Web of Science Record created on 2010-11-30, modified on 2016-08-09

Egg predators of an endemic Italian salamander, Salamandrina perspicillata (Savi, 1821)

We report new aquatic predators feeding on Northern spectacled salaman - der eggs, Salamandrina perspicillata, an endemic Italian species. Eggs were preyed upon by the leech, Trocheta bykowskii, and the trichopteran larvae of Potamophylax cingulatus and Halesus appenninus. Riassunto. In torrenti dell'Umbria e delle Marche e stata osservata la predazione di uova di Salamandrina perspicillata da parte di una specie di sanguisuga, Trocheta bykowskii e da larve di tricotteri appartenenti alle specie Potamophylax cingulatus e Halesus appenninus.

Prolactin-based "Water-drive Theory" in Migratory Salamanders: Some Disprovable Data"

Prolactin-based "Water-drive Theory" in Migratory Salamanders: Some Disprovable Data"

The phenology of a rare salamander ( Salamandra infraimmaculata ) in a population breeding under unpredictable ambient conditions: a 25 year study

This is a long-term study (1974-1999) on the phenology of the rare, xeric- inhabiting salamander Salamandra infraimmaculata in a small isolated population during the breeding season near the breeding ponds on Mt. Carmel. This is a fringe area of the genus’ south-easternmost Palaearctic distribution. Salamanders were captured during the 25 year long study. The first years up to the 1980s the total number of salamanders increased but during the last years there seems to have been a decline. Although this could be a phase in normal population cyclic oscillations nevertheless when compared with long-term data on a European Salamandra it does not seem so. The interpretation of the species’ status is dependent on numbers of salamanders captured as well as on the duration of the study. These subjects are reviewed and discussed in this paper.

Molecular DNA variation among Triturus vittatus vittatus (Urodela) from different breeding sites at the southern limit of its distribution

Molecular DNA variation among Triturus vittatus vittatus (striped newt) from different breeding sites at the southern limit of the species distribution (where environmental conditions are most extreme) was studied by the random amplification of polymorphic DNA (RAPD) method that has been found to be appropriate for other Triturus species. Altitudes of the localities ranged between 15-740 m a.s.l. Of the 20 primers employed, OPA-16 was the only one suitable for T. vittatus, revealing a differ - ent band pattern for different populations. Genetic similarity was calculated by band sharing, which demonstrated a high similarity among the Israeli populations.

Sexual dichromatism in the marbled salamander, Ambystoma opacum

Reports of sexual dichromatism in salamanders are rare and have been generally restricted to a few species in the families Hynobiidae and Salamandridae. We used image analysis techniques to examine sexual dichromatism in the marbled salamander, Ambystoma opacum (Gravenhorst, 1807). We measured the average hue of white saddles on male and female marbled salamanders (n = 118), as well as the proportion of white dorsal surface area relative to the black dorsal surface area, to determine the extent of sexual dichromatism in this species. We also tested whether patterning and coloration were correlated with body size or relative body mass. Males had significantly whiter saddles and higher relative proportions of white coloration on their dorsal surfaces than did females. Furthermore, the relative proportion of white areas on the dorsum was positively correlated to body condition in both males and females. Body size was not correlated with hue or proportion of white area on the dorsum. To our knowledge, we report the first confirmation of sexually dimorphic coloration in the ambystomatid salamander family, extending the known distribution of sexual dichromatism in the order Caudata.